A scheduled third trial of Malcolm Rewa for the murder of Susan Burdett is in doubt.
A directive in November on behalf of the Attorney-General reversing a stay on the matter appeared to clear the way for a third trial, according to the High Court case file, examined by the Herald.
But Rewa's lawyer Paul Chambers has claimed the process is unlawful.
Eight weeks have been set aside next February to try Rewa again for the 1992 murder of Ms Burdett who was raped and bludgeoned in her Papatoetoe home.
A stay has never before been lifted in New Zealand and academic and lawyers have queried whether a mechanism exists to do it.
The Crown and Chambers agree that case law indicates that a stay does not prevent a further prosecution, once the stay is lifted.
And the Crown submits that the reversal of the stay imposed in 1998 clears the way for Rewa to be tried again.
But Chambers has informed the court that the process of lifting the stay is invalid as legislation only gave the Attorney-General power to enter a stay, not to lift one.
Neither the Crimes Act nor the Criminal Procedure Act had an express provision that afforded the power to lift a stay.
"The proceeding is and remains stayed," Chambers noted in a memorandum in December.
Presiding judge, Justice Simon Moore, noted on the file that whether Rewa goes to trial again will be decided after a two-day hearing in May.
At that hearing, Chambers will challenge the "purported decision to lift the stay", made in a directive in November by the Deputy Solicitor-General on behalf of the Attorney-General.
Chambers will file applications for judicial review of that decision and for a stay of proceedings against Rewa, to be heard together.
Rewa is serving 22 years' in prison for the rapes of Burdett and 24 other women. It is the longest finite sentence for rapes committed before 1993.
The stay was put in place in December 1998 after two juries failed to decide whether Rewa, whose DNA was at the scene, was guilty of murdering Burdett.
The Crown is seeking to try Rewa a third time following the decision of the Privy Council in 2015 to quash Teina Pora's convictions for her rape and murder.
Pora was twice convicted and spent 22 years in prison. He has received an apology from the Government and $3.5 million compensation.
The "reversal of stay of proceedings" document, signed by Deputy Solicitor-General Brendan Horsley, notes that Pora was already convicted of the murder at the time the two juries failed to reach a decision regarding Rewa, that Pora's conviction has since been quashed, that there is now no one held to account for the murder, that there is sufficient evidence to support the murder charge against Rewa, that there is public interest in an offender being held to account and "that the ends of justice would be best answered by trying Malcolm Rewa for the murder of Susan Gail Burdett a third time."
The May hearing will decide whether that occurs.
Meanwhile, Rewa, 65, was escorted under guard this month for unspecified medical treatment at North Shore Hospital.
A patient at the hospital told the Herald he was in the same room when Rewa's name was called out by staff.
The patient, who asked not to be named, said that Rewa was chained to "the biggest prison guard you will see" with another close by. Rewa wore track pants and a singlet and now had little hair.
A spokesman said Corrections would not comment on the movement of prisoners but said it had an obligation to access health services in the community for inmates where such treatment was not available in prison.
"Public safety is Corrections number one priority and any prisoner who is required to attend a hospital appointment would be accompanied by experienced Corrections officers."
The case that won't go away
: Burdett raped and bludgeoned to death in her Papatoetoe home.
: Teina Pora convicted of her rape and murder.
: Rewa, whose DNA was found at the scene, convicted of Burdett's rape but two juries fail to decide whether or not he murdered her. Solicitor-General enters a stay.
: Pora, having successfully appealed his convictions, is convicted at a new trial.
: Privy Council quashes Pora's convictions and recommends he not be tried again.
: Pora receives Government apology and compensation.
: Deputy Solicitor-General (for the Attorney-General) directs that the stay against Rewa be lifted.
: High Court hearing to determine whether lifting the stay is lawful.